Python实现航空公司等级计算时遇NameError: name未定义问题求助

Hey there! Let's work through this error and get your program running properly. That NameError: name 'flight_miles' is not defined is happening because your calculate_flight_miles_earned function doesn't return the calculated value—but there are a few other small bugs we need to fix too. Let's break it down step by step:

Key Issues & Fixes #

1. calculate_flight_miles_earned doesn't return a value #

Right now, you calculate flight_miles inside the function, but never send it back to the main code. That means when you do flight_miles = calculate_flight_miles_earned(flights_purchased), flight_miles ends up as None, which causes errors later. Add a return flight_miles at the end of the function:

def calculate_flight_miles_earned(flights_purchased):
    flight_miles = 0
    if flights_purchased == 0:
        flight_miles = 100
    elif flights_purchased == 1:
        flight_miles = 5
    elif flights_purchased == 2:
        flight_miles = 15
    elif flights_purchased == 3:
        flight_miles = 30
    elif flights_purchased > 3:
        flight_miles = 60
    return flight_miles  # Add this line!

2. final_evaluation has incorrect parameters & undefined variables #

Your function definition includes output_flight_tier as a parameter (which you don't use), and when you call it in main(), you reference flights—a variable that doesn't exist. Let's fix the function to use flights_purchased (since your evaluation is about flight count) and remove the unused parameter:

def final_evaluation(flights_purchased):
    evaluation = ""
    if flights_purchased < 15:
        evaluation = "You are not a frequent flyer"
    elif flights_purchased > 15:
        evaluation = "You are a frequent flyer"
    # Handle the edge case for exactly 15 flights
    else:
        evaluation = "You are a frequent flyer"
    return evaluation

Then update the call in main() to:

evaluation = final_evaluation(flights_purchased)

3. output_point uses wrong parameters & undefined variables #

This function is set up to accept four functions as parameters, but you actually need to pass the calculated values (flights_purchased, flight_miles, evaluation). Rewrite the function to use these values instead:

def output_point(flights_purchased, flight_miles, evaluation):
    print(f"The number of flights you have purchased is {flights_purchased}")
    print(f"The total # of miles earned from flights you have purchased is {flight_miles}")
    print(f"The final evaluation is: {evaluation}")

And update the call in main() to:

output_point(flights_purchased, flight_miles, evaluation)

4. get_flights_purchased has a broken loop condition #

The line while flights_purchased is not int: doesn't work—flights_purchased starts as 0 (an integer), so the loop never runs. Instead, use an infinite loop that breaks only when valid input is received:

def get_flights_purchased():
    while True:
        try:
            flights_purchased = int(input("Please enter the number of flights that you purchased this month: "))
            return flights_purchased
        except ValueError:
            print('That is not a number. Please provide a whole number.')

5. Minor Tier Label Consistency #

You have duplicate "MVP GOLD" labels for 30 miles and over 30 miles. To make it clearer, you could adjust the highest tier, like:

elif flight_miles > 30:
    print("You are in the MVP GOLD ELITE airline tier!")

Full Corrected Code #

Here's the complete fixed program:

def get_flights_purchased():
    while True:
        try:
            flights_purchased = int(input("Please enter the number of flights that you purchased this month: "))
            return flights_purchased
        except ValueError:
            print('That is not a number. Please provide a whole number.')

def calculate_flight_miles_earned(flights_purchased):
    flight_miles = 0
    if flights_purchased == 0:
        flight_miles = 100
    elif flights_purchased == 1:
        flight_miles = 5
    elif flights_purchased == 2:
        flight_miles = 15
    elif flights_purchased == 3:
        flight_miles = 30
    elif flights_purchased > 3:
        flight_miles = 60
    return flight_miles

def output_flight_tier(flight_miles):
    if flight_miles == 0:
        print("You haven't flown with us yet, so you don't have a flight tier.")
    elif flight_miles == 5:
        print("You are in the economy airline tier")
    elif flight_miles == 15:
        print("You are in the MVP airline tier")
    elif flight_miles == 30:
        print("You are in the MVP GOLD airline tier")
    elif flight_miles > 30:
        print("You are in the MVP GOLD ELITE airline tier!")

def final_evaluation(flights_purchased):
    evaluation = ""
    if flights_purchased < 15:
        evaluation = "You are not a frequent flyer"
    else:
        evaluation = "You are a frequent flyer"
    return evaluation

def output_point(flights_purchased, flight_miles, evaluation):
    print(f"The number of flights you have purchased is {flights_purchased}")
    print(f"The total # of miles earned from flights you have purchased is {flight_miles}")
    print(f"The final evaluation is: {evaluation}")

def main():
    flights_purchased = get_flights_purchased()
    flight_miles = calculate_flight_miles_earned(flights_purchased)
    output_flight_tier(flight_miles)
    evaluation = final_evaluation(flights_purchased)
    output_point(flights_purchased, flight_miles, evaluation)

main()

Now when you run this, it should accept input, calculate miles correctly, display your tier, and give you the frequent flyer evaluation without any NameErrors!

内容的提问来源于stack exchange，提问作者user9825297